Abstract
The neurologist has a continuously expanding arsenal of ancillary investigations at hand. Good clinical skills are mandatory to put the patient on the right diagnostic track and to ensure correct interpretations of the results. Every investigation ordered should serve a specific purpose and help to answer a well-considered and well-formulated question. Close cooperation and, preferentially, personal communication with appropriate colleagues such as radiologists, neurophysiologists, and geneticists are mandatory. Given the book’s focus on bedside skills, the following overview of neuroimaging, neurophysiology, ultrasound techniques, laboratory evaluations of blood and cerebrospinal fluid, genetic testing, and neuropsychological evaluation is short but covers many elementary technical and clinical facts relevant to the general neurologist. Clinical neurophysiology is discussed in somewhat greater detail, since it is the domain of the neurologist in many countries.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsNotes
- 1.
Sir Godfrey Newbold Hounsfield (1919–2004), English electrical engineer who received a shared Nobel Prize for Physiology or Medicine in 1979 for his contributions to CT.
- 2.
2Following a lumbar puncture, diffuse meningeal contrast enhancement in the spine may be seen for days or weeks, and, although not pathological, this may lead to diagnostic confusion.
- 3.
3Simplified, if you perform a large number of tests, there is a statistical chance that some of the results will be false-positive simply because you have performed a large number of tests. Adjusting for multiple comparisons ensures that this “chance significance” is corrected for. The problem of unadjusted multiple comparisons when using fMRI has been elucidated elegantly by Bennet et al., who performed fMRI on a dead salmon. The fish was shown photos of people with different facial expressions and asked to guess the emotions they were having. Using standard acquisition, preprocessing, and analysis techniques, Bennett et al. (2009) showed that active voxel clusters could be observed in the dead salmon’s brain when statistical thresholds remained uncorrected. Upon correction for multiple testing, the positive results disappeared.
- 4.
4 For instance, a C8 nerve root lesion may lead to EMG abnormalities in the latissimus dorsi (thoracodorsal nerve), triceps, extensor digitorum communis, extensor indicis proprius (radial nerve), abductor pollicis brevis (median nerve), flexor carpi ulnaris, and flexor digitorum profundus muscles of the fourth and fifth digits (ulnar nerve), as well as in the small hand muscles (ulnar and median nerve). In contrast, an ulnar nerve lesion will leave the latissimus dorsi, triceps, extensor digitorum communis, extensor indicis proprius, and abductor pollicis brevis muscles intact.
- 5.
5 Needle examination of the sternocleidomastoid muscles carries a sensitivity similar to examination of the tongue in patients with bulbar symptoms and may be better tolerated by the patient.
- 6.
6 In contrast to Doppler sonography, CT/MR angiography is more time-consuming but allows complete imaging of the intracranial and neck vessels, including the aortic arch, which is why CT/MR angiography can also detect carotid artery stenosis distally and proximally from the carotid artery bifurcation.
- 7.
7 Tau proteins are abundant in the CNS and essential for stabilizations of microtubules in neurons. High total tau levels can be used as a marker of cortical axonal degeneration. Phosphorylation of tau is believed to be specific for AD and related tauopathies. Beta-amyloid is the main constituent of amyloid plaques in the brains of patients with AD. Since amyloid accumulates within the neurons and cerebral vessel, its amount in CSF is decreased in AD.
- 8.
8 Similar to tau protein, NFL light protein is an important component of neuronal axons. The CSF level of NFL light protein increases in disorders with neuronal damage and axonal degeneration and correlates with the amount of damage.
References and Suggested Reading
Albert MS, et al. The diagnosis of mild cognitive impairment due to Alzheimer’s disease: recommendations from the National Institute on Aging-Alzheimer’s Association workgroups on diagnostic guidelines for Alzheimer’s disease. Alzheimers Dement. 2011;7:270–9.
Aminoff MJ. Aminoff’s electrodiagnosis in clinical neurology. 6th ed. London: Saunders; 2012.
Bennett CM, Baird AA, Miller MB, Wolford GL. Neural correlates of interspecies perspective taking in the post-mortem atlantic salmon: an argument for proper multiple comparisons correction. In: 15th annual meeting of the Organization for Human Brain Mapping, San Francisco, 2009.
Cocito D, Isoardo G, Ciaramitaro P, et al. Terminal latency index in polyneuropathy with IgM paraproteinemia and anti-MAG antibody. Muscle Nerve. 2001;24:1278–82.
Douglass CP, Kandler RH, Shaw PJ, McDermott CJ. An evaluation of neurophysiological criteria used in the diagnosis of motor neuron disease. J Neurol Neurosurg Psychiatry. 2010;81:646–9.
Fisch B. Fisch and Spehlmann’s EEG primer: basic principles of digital and analog EEG. 3rd ed. Amsterdam: Elsevier; 1999.
McKhann GM, et al. The diagnosis of dementia due to Alzheimer’s disease: recommendations from the National Institute on Aging-Alzheimer’s Association workgroups on diagnostic guidelines for Alzheimer’s disease. Alzheimers Dement. 2011;7:263–9.
National adult reading test, 2nd Edition. Hazel E. Nelson with Jonathan Willison. 1991, NFER-Nelson.
Rumboldt Z, Castillo M, Huanq B, Rossi A. Brain imaging with MRI and CT: an image pattern approach. 1st ed. Cambridge: Cambridge University Press; 2012.
Sorbi S, Hort J, Erkinjuntti T, Fladby T, Gainotti G, Preston CD, Shapiro B. Electromyography and neuromuscular disorders: clinical-electrophysiologic correlations. 2nd ed. Oxford: Butterworth-Heinemann; 2005.
Valdueza JM, Schreiber SJ, Roehl JE, Klinebiel R. Neurosonology and neuroimaging of stroke. 1st ed. Stuttgart: Thieme; 2008.
Warren JD, Schott JM, Fox NC, et al. Brain biopsy in dementia. Brain. 2005;128:2016–25.
Wilbourn AJ. Clinical neurophysiology in the diagnosis of amyotrophic lateral sclerosis: the Lambert and the El Escorial criteria. J Neurol Sci. 1998;160:S25–9.
Author information
Authors and Affiliations
Rights and permissions
Copyright information
© 2014 Springer-Verlag London
About this chapter
Cite this chapter
Kondziella, D., Waldemar, G. (2014). Ancillary Investigations. In: Neurology at the Bedside. Springer, London. https://doi.org/10.1007/978-1-4471-5251-4_5
Download citation
DOI: https://doi.org/10.1007/978-1-4471-5251-4_5
Published:
Publisher Name: Springer, London
Print ISBN: 978-1-4471-5250-7
Online ISBN: 978-1-4471-5251-4
eBook Packages: MedicineMedicine (R0)